By Michael Safi
Delhi (click here) has been blanketed in a toxic fog the morning after the Hindu festival of Diwali, when hundreds of thousands of people in the Indian capital celebrate by setting off crackers and fireworks.
Air quality in the Indian capital, one of the world’s most polluted cities, is usually very poor due to road dust, open fires, vehicle exhaust fumes, industrial emissions and the burning of crop residues in neighbouring states.
But the density of some harmful particles and droplets in the air spikes for days after Diwali and can reach up to 42 times the safe limit.
An air quality station at the US embassy in Chanakyapuri, one of the city’s greener districts, recorded a PM2.5 level of 999 on Monday morning. India’s pollution control board sets the safe limit for PM2.5 – which measures particulate matter smaller than 2.5 micrometres – at 60.
By contrast, the highest PM2.5 level recorded in London on Monday morning was 139, at a measuring station in Farringdon. Averages tend to be far lower across the year, at about 16, according to a 2010 study....